Blade for a gas turbine engine

Abstract

A blade for a gas turbine engine comprises an aerofoil body having a suction side, a pressure side, and a trailing edge. An internal cooling passageway is provided in the aerofoil body, and an ejection slot in fluid communication with the cooling passage and provided at the trailing edge of the aerofoil body. The ejection slot is defined between a pressure side wall and a suction side wall. Both the suction side wall and the pressure side wall include a mid-section and a trailing edge section adjacent the mid-section, and the thickness of the suction side wall and the pressure side wall reduces to define a taper with a wedge angle less than or equal to 20 degrees.

We claim: 
     
       1. A blade for a gas turbine engine, the blade comprising:
 an aerofoil body having a suction side, a pressure side, and a trailing edge; 
 an internal cooling passageway provided in the aerofoil body; and 
 an ejection slot in fluid communication with the cooling passage and provided at the trailing edge of the aerofoil body; 
 wherein the ejection slot is defined between a pressure side wall and a suction side wall; and 
 wherein both the suction side wall and the pressure side wall include a mid-section and a trailing edge section adjacent the mid-section, and wherein each of the suction side wall and the pressure side wall has a thickness that reduces in a direction toward the trailing edge beginning at a transition from the mid-section to the trailing edge section to define a taper with a wedge angle equal to 20 degrees; 
 wherein each of the pressure side wall and the suction side wall define an internal gas washed surface and an external gas washed surface that meet at a terminal end of the trailing edge section; 
 wherein the thickness of the pressure side wall and the thickness of the suction side wall each reduces such that the internal and external gas washed surfaces of the trailing edge sections have continuous curvature beginning at the transition from the mid-section to the trailing edge section and extending to the terminal end of the trailing edge sections and the thickness of the trailing edge sections reduces to half that of a maximum thickness of the trailing edge section; 
 wherein the continuous curvature of the internal and external gas washed surfaces of the trailing edge sections has a portion with a smallest radius of curvature at the terminal end of the trailing edge section, the portion is spaced apart from the internal and external gas washed surfaces by one quarter of the thickness of the pressure side wall and one quarter of the thickness of the suction side wall; and 
 wherein the continuous curvature is defined as a constant curvature or a curvature that changes gradually. 
 
     
     
       2. The blade according to  claim 1 , wherein the maximum thickness of the trailing edge section of the suction side wall and/or the pressure side wall is at least 5% of the width of the ejection slot measured in a thickness direction of the blade. 
     
     
       3. The blade according to  claim 1 , wherein the terminal end of the trailing edge of the suction side wall is chordally offset from the terminal end of the trailing edge section of the pressure side wall. 
     
     
       4. The blade according to  claim 1 , wherein the terminal end of the trailing edge section of the suction side wall is chordally aligned with the terminal end of the trailing edge section of the pressure side wall. 
     
     
       5. The blade according to  claim 1 , wherein the blade is a turbine blade. 
     
     
       6. A gas turbine engine comprising the blade according to  claim 1 . 
     
     
       7. The blade according to  claim 1 , wherein the concave curvature is adjacent the terminal end of the trailing edge section. 
     
     
       8. The blade according to  claim 1 , wherein each terminal end of the trailing edge sections has both a concave and a convex curvature when viewed in a radial direction relative to an axis of the gas turbine engine.